Halogenation reaction, types of halogenation reaction, free radical halogenation, electrophilic aromatic substitution, addition of halogen, application, bromination, chlorination, iodination reaction

1. HALOGENATION REACTION
SUBMITTED BY:
UPASANA SHARMA
(Pharmaceutical Chemistry)
M. Pharma II SEM
Noida Institute of Engineering and Technology
Greater Noida
SUBMITTED TO:
DR. RAKHI MISHRA
(PROFESSOR)

2. 1.Free radical halogenation = halogen atom replaces a hydrogen atom in an organic compound.
2. Free radicals, which are highly reactive species with unpaired electrons.
3.The reaction occurs in the presence of a halogen, chlorine (Cl2) or bromine (Br2), and a source of
energy, such as heat or light
FREE RADICAL HALOGENATION REACTION :

3. • APPLICATION:
• Synthesis of Halogenated Organic Compounds: This allows the selective introduction of halogens
at specific positions in the molecule,
• Preparation of Alkyl Halides: Alkyl halides find applications as intermediates in the synthesis of
pharmaceuticals, agrochemicals, and other organic compounds.
• Polymerization Reactions: polymerization of monomers. For example, the reaction of vinyl
chloride (CH2=CHCl) with itself, initiated by free radicals, leads to the formation of polyvinyl
chloride (PVC), a widely used polymer.
• Radical Substitution Reactions: Free radical halogenation serves a model for understanding radical
substitution reactions, which involve the replacement of one functional group by another.

4. Electrophilic aromatic substitution (EAS)
1.An electrophile (electron-deficient species) replaces a hydrogen atom on an aromatic ring.
2. It involves the attack of the electrophile on the aromatic system, leading to the formation of a new substituted
aromatic compound.

5. APPLICATION:
• Nitration: nitro group (-NO2) onto an aromatic ring. The nitronium ion (NO2+) is the electrophile
generated in the reaction.
• Halogenation: A halogen (Cl, Br, or I) on the aromatic ring. The electrophile can be a halogen molecule
or a halonium ion.
• Friedel-Crafts Alkylation: An alkyl group (-R) to an aromatic ring. Alkyl halides and carbocations are
electrophiles.
• Friedel-Crafts Acylation: an acyl group (-COR) onto an aromatic ring. Acyl halides or acylium ions are
electrophile
• Sulfonation: a sulfonic acid group (-SO3H) to an aromatic ring. Sulfur trioxide (SO3) or sulfuric acid
(H2SO4) are electrophiles.
• Nitrosation: a nitroso group (-NO) to an aromatic ring. Nitrous acid (HNO2) is a electrophile.

6. The addition of halogens to alkenes to form alkynes is known as halogenation of alkynes.
It involves the addition of two halogen atoms across a carbon-carbon triple bond, resulting in the conversion of
the alkyne into tetrahaloalkane. This reaction is typically carried out using halogens such as chlorine or bromine
in the presence of a suitable solvent or catalyst.
ADDITION OF HALOGEN:

7. APPLICATION:
• Synthesis of Tetrahaloalkanes: Compounds containing four halogen atoms, intermediates in the
synthesis of various organic compounds, including pharmaceuticals and agrochemicals.
• Preparation of Organometallic Compounds: Tetrahaloalkanes obtained from halogenation of
alkynes can be used as precursors for the synthesis of organometallic compounds. By reacting the
tetrahaloalkane with a metal, such as magnesium (Mg) or lithium (Li), organometallic species
like Grignard reagents or organolithium compounds can be formed, which are valuable for
various synthetic transformations.

8. Chlorination Bromination
Florination
Iodination
CH3COOH + 2I = CH2ICOOH + HI
H2C = CH2 + HI = CH2ICH3

9. THANK YOU